Android app on Google Play

Circle

Drawing of a circle chord
A chord is a line segment between two points on the circle’s periphery.

Each of these two points is the distance r (the radius) from the center point. As you can see in the figure to the right, the chord and the two radiuses are forming a triangle. Therefore it’s possible to determine the chord length crd(α) by use of trigonometry:

crd(alpha)=2*r*sin(frac{alpha}{2})

where r = radius and α = angle at the center point.

Calculate the chord length

Radius (r): 
Angle (α):